Die changing apparatus

ABSTRACT

Apparatus particularly suited for changing dies in extrusion presses having a ram movable along a path. The apparatus includes a guide track which intersects the path of movement of the press ram. A plurality of die holders are mounted for movement in the guide track. Means are provided for selectively driving the holders along the guide track to being desired ones into alignment with the ram and means are provided for locking the holders in position.

United States Patent Inventor Alois J. Moos Kew Gardens, N.Y. Appl. No. 853,675 Filed Aug. 28, 1969 Patented Beat. 28, 1971 Assignee Company Grand Rapids, Mich.

DIE CHANGING APPARATUS 7 Claims, 4 Drawing Figs.

US. Cl.

Field of Search Gull & Western Industrial Products [56] References Cited UNITED STATES PATENTS 3,139,183 6/1964 Elkan 72/263 3,147,863 9/1964 Rosenthal 72/263 3,357,226 12/1967 Snell 72/263 Primary Examiner-Charles W. Lanham Assistant Examiner-Robert M1 Rogers Attorney-Meyer, Tilberry and Body ABSTRACT: Apparatus particularly suited for changing dies in extrusion presses having a ram movable along a path. The apparatus includes a guide track which intersects the path of movement of the press ram. A plurality of die holders are mounted for movement in the guide track. Means are provided for selectively driving the holders along the guide track to being desired ones into alignment with the ram and means are provided for locking the holders in position.

PATENTEDnzczaum Q 3,630,055

SHEET 2 BF 2 7.4-. 42 46 INVENTOR. ALOIS T. oos

ATTORNEYS.

DIE CHANGING APPARATUS The present invention is directed toward the press art and, more particularly, to an improved apparatus for changing dies in a forming press.

The invention is especially suited for changing dies in an extrusion press and will be described with particular reference thereto; however, as will be appreciated, the invention is capable of much broader application and could be utilized for changing dies in a variety of different types of presses.

In the extrusion of various metals, the dies must normally be cleaned, cooled and lubricated following each push. Otherwise, the die heats up and is washed-out in a comparatively short time. Alternately, in certain types of extrusion processes, a number of different types of dies must be utilized sequentially during operation on a single billet. For example, when a solid billet is to be pierced in the extrusion press, a blind flange replaces the die and the piercer or ram is actuated into the billet. This causes the billet material to be upset back toward the piercer. When the piercer has approached within an inch or two of the blind flange, the blind flange is replaced by a second flange or die having an opening aligned with and corresponding in diameter to the piercer. Subsequent forward movement of the piercer causes the l or 2-inch section of billet material to be extruded and the billet is thus completely pierced. Thereafter, the second flange is replaced by an extrusion die and extrusion of the billet completed.

As is apparent from the above, if the press is to be capable of rapid cycle operation, means must be provided for quickly changing dies. in the past, two different types of die changing mechanisms have been used. One comprised a reciprocable slide-type die carrying member provided with two or three die holders, whereas, the other comprised an oscillated or rotated type member similarly provided with a plurality of die holders. The members were positioned relative to the press in a manner which permitted them to function to selectively index any one of their associated dies into working position.

Although, these prior mechanisms functioned satisfactorily they had certain distinct disadvantages. First, their very nature limited the number of die holders or index positions which they could provide. For example, in the slide-type, each additional position increased the length of the slide member. Similarly, in order to increase the number of positions available with the rotatable-type it was necessary to increase the diameter of the rotatable die supporting member. Because of normal space limitations, these prior mechanisms were effectively limited to approximately four die positions.

in addition to the limitation on the number of positions available, the prior mechanisms required a fixed size space of definite shape in which to operate. As a consequence press designers were required to design the press, to a degree, to accommodate the die changing mechanism. This produced design compromises which were often undesirable.

The subject invention provides an improved die changing mechanism which is capable of providing an extremely large number of dies or die carriers. Thereby allowing much greater cycling speed. Additionally, the mechanism provided can be arranged to fit into substantially any shape of space thereby eliminating strict design limitations on the press. Further, the mechanism is simple and inexpensive to manufacture and operate.

In accordance with the present invention an improved die changing mechanism is provided for a press of the type including a ram reciprocated along a working path and arranged to cooperate with a die positioned along the path for forming a workpiece therebetween. The mechanism includes guide means defining a closed loop guide path which intersects the path of movement of the ram. A plurality of die carriers are mounted in the guide means and arranged for movement relative thereto along the guide path. Drive means are associated with the guide means for selectivey moving the die members along the path and means positioned adjacent the intersection of the working path and said guide path for selective looking a die carrier in working position.

As can be seen, since the die carriers are independently movable along a closed loop a guideway and are not mechanically connected to any movable slides or rotary members, there are substantially no limitations on the shape or layout of the guideway. Consequently, the die changing mechanism can t be arranged to fit within substantially any shape of space.

Further, merely by lengthening the guideway the number of die carriers can be increased.

Accordingly, a primary object of the invention is the provision of a die changing or indexing mechanism which permits a large number of dies to be handled, thereby increasing the cycle rate of the associated press.

Another object is the provision of a die changing mechanism which does not require operational space of any fixed shape.

A further object of the invention is the provision of a die indexing mechanism which can be arranged to carry substantially any number of dies.

Yet another object is the provision of mechanism of the type described which is simple to manufacture and operate. These and other objects and advantages will become apparent from the following description when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a longitudinal cross-sectional elevational view through a typical hydraulic extrusion press provided with a die changing or indexing mechanism formed in accordance with the preferred embodiment of the invention;

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1 and showing the die changing mechanism in detail; and,

FIGS. 3 and 4 are cross-sectional views taken on line 3+3 and 4-4, respectively of FIG. 2.

Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the in vention only, and not for the purpose of limiting same, FIG. 1 shows a cross-sectional elevation through a relatively conventional extrusion press A provided with a die changing apparatus B formed in accordance with the preferred embodiment of the present invention.

The actual design and construction of extrusion press A is not of particular importance to the invention; however; as shown, it includes a main frame 10 comprised of crosshead members 12 and 14 interconnected by four large diameter tie rods 16 and nuts 18.Crosshead forming member 12, in effect, comprises the bed plate of the press and supports the extrusion dies, whereas, the crosshead forming member 14 carries a large diameter hydraulic cylinder 20 which receives a piston 22 which carries a elongated cylindrical ram 24 on its righthand end. Actuation of piston 22 causes the ram to be driven along a working path indicated by the center line 26. The piston 22 is returned to the position shown solid by additional smaller diameter cylinders not shown.

Positioned along the path 26 is a pressure container 28 and an extruding die assembly 30. Pressure container 28 functions to contain the billet being extruded an resist the radially directed pressure forces generated during the extrusion operation. As shown, the container 28 includes a central bore or billet receiving opening 32 which is coaxial with the path 26 and the ram 24. The die assembly 30 includes the usual extrusion die 34 and backing rings 36 through 38. As can be appreciated with a billet of material positioned within bore 32 actuation of the ram 24 to the right causes the billet to be placed under extremely high pressures and extruded through the center opening 40 of die 34 and exit from the press through the opening 42 formed in the crosshead forming member 12.

As previously discussed, following each extrusion operation the die 34 must be cooled, cleaned and relubricated. In order to accomplish this while permitting the machine to attain a substantial number of cycles per time period, it is the practice to provide automatic die changing apparatus so that while one die is being serviced, another can be in operation. As mentioned, these have included a member which supported a plurality of dies or die carriers and was indexable to move selected ones of the dies into position between the container 28 and the backing rings. As previously discussed, in order to provide a sufficient number of dies the reciprocated or rotated members had to be relatively large and took up the unused amount of space. Additionally, they limited the press designer.

In accordance with the present invention there is provided a changing or indexing mechanism which overcomes these problems and permits a large number of die carriers to be utilized in a limited amount of odd shaped space. Specifically, according to the preferred embodiment, the apparatus B includes a die carrier supporting guideway forming means 40 which, as best shown in FIG. 2, defines a closed loop guide path which lies in a plane generally perpendicular to the working path 26 and intersecting the working path at a single point.

Although the guideway forming means could be of many different constructions and have substantially any specific layout, in the preferred embodiment it is of generally elliptical shape and is defined by a first guide member 42 which is of L- shaped cross section and arranged to define the outermost surface of the guide track. As can be seen, the member 42 is supported directly from the crosshead or end plate member 12 and a laterally extending support member 44 which, in the embodiment under consideration, is simply a metal frame plate joined to the side of the end plate 12. The member 42 is joined to the end plate and the support frame 44 in any convenient manner such as through the use of a plurality of machine screws 46.

Positioned at the inside of the guideway is a pair of L- shaped guide members 50,51 which are similarly connected to the end plate 12 and the support frame 44 by machines screws 52. As can be seen from FIGS. 3 and 4, the members 50,51 in combination with the outer member 42 define the oval or elliptical guide path.

Arranged to be received within the guide path and movable therealong are a plurality of die holders 54. As can be appreciated, the die holders 54 could have a variety of constructions and configuration; however, in the embodiment under consideration they are of generally cylindrical shape. Each of the die carriers 54 has an outer rim portion 56 which is adapted to and engage in a guide groove 58 formed in the inner surface of the guide member 42. A similar guide groove 60 is formed on the surface of each of the members 50,51. The cooperating grooves 58 and 60 provide a guide or retainer track for the die carriers 54 and function to maintain them properly oriented during their movement about the track.

As can best be seen, from FIG. 4, each of the die carriers 54 includes a central opening 62 and a recess 64. The recess 64 receives the die member 34. These die members 34 would, of course, vary substantially depending upon the particular function being performed. The dies are releasably retained in the die carrier in any convenient manner such as through the use of a clamp ring 56 connected to the die carrier by a plurality of machine screws 68. These features of the device are not of particular importance and could take many embodiments.

In the embodiment under consideration, the die carriers 54 are pivotally interconnected by links 66 which are joined by pivot pins 68 to ears or tabs 70 which extend outwardly on diametrically opposite sides of the die carriers 54. As can be appreciated, the entire die carrier assemblage is of a length such that it is properly fitted correct for the pathway or guideway forming means 40.

In order to index or move the dies or die assemblage about the pathway, there are provided sprocketlike members 74 and 76. Each of these sprocketlike members are mounted on a separate rotatable shaft. Note that the member 74 is keyed to a support shaft 78 whereas member 76 is similarly keyed to a shaft 80 which extends outwardly from the end plate 12. The shafts 78,80 are rotatably mounted in suitable bearings not shown. Each of the members 74,76 is identical in construction and includes four recessed portions 82 which are arranged to engage the outer surface of the die carriers 54. Inwardly extending grooves are formed in the portions 82 to receive the outwardly extending portions 56 of the die carriers.

As can be appreciated, by rotating either of the members 74, 76 the die carriers 54 can be moved about the path to bring selected ones of them into alignment with the path of movement of the ram 24. In the FIG. 2 showing, the die carrier at the position labeled E is in the extruding position. Many different types of drive mechanisms could be provided for indexing the die carriers about the pathway. In the embodiment under consideration, a motor and gear box assembly 84 is shown supported from the top of the frame plate 44 and drivingly interconnected with the shaft 78 by a sprocket and chain drive 86. The motor and gear unit 84 is, of course, controlled by conventional circuitry to provide the desired movement of the member 74.

When the die is in position at location B means are provided to firmly lock it against any undesired movement and maintain it properly located relative to the ram. These means could take many forms but are shown as comprised of a plate or lock member 88 which is mounted in a guideway forming assembly 90. The assembly 90 comprises two guide plates which for a guideway engaging opposite sides of the plate member 88. A double acting hydraulic cylinder 90 has its piston rod 92 connected to the right-hand edge of the plate member 88. The opposite edge of the plate member 88 is curved to conform with the outer surface of the cylindrical die carriers 54. Additionally, a groove not shown, is formed in the cylindrical face of the plate member for receiving the outwardly extending portions 56 of the die carriers. Actuation of the cylinder 90 causes the plate member 88 to be moved inwardly to position shown the die carriers are firmly gripped between the member 76 and the member 88 to hold them during the extruding operation. When it is desired to change dies the cylinder 90 is, of course, actuated to move the plate 88 to the right permitting free rotation of the die assemblage about the guideway. The actuation of the cylinder can be interlocked with the motor unit.

The invention has been described in great detail sufficient to anyone of ordinary skill in the press art to make and use the same. Obviously, modifications and alterations of the preferred embodiment will occur to others upon a reading and understanding of the specification and it is our intention to include all such modifications and alterations as part of our invention in so far as they come within the scope of the appended claims.

Having thus described my invention, I claim:

1. A press including a frame, ram means reciprocatingly carried by said frame for reciprocation along a working path between first and second positions, a plurality of die carrier units, flexible connecting means for flexibly interconnecting said die carrier units into a closed die carrier loop, supporting guideway means for supporting and guiding said die carrier loop, said supporting and guideway means being in the form of a closed loop guide path which intersects said working path at a single point, indexing drive means for indexing said die carrier units around said guide path to sequentially position each of said die carrier units at said single point, and actuable locking means for sequentially engaging and locking said die carrier units at said single point for cooperation with said ram means.

2. The device of claim 1 wherein said indexing drive means includes a rotatable member engaging said die carrier units in seriatim order.

3. The device of claim 2 wherein said rotatable member is in continuous engagement with at least one of said die carrier units.

4. The device of claim I wherein said locking means comprises reciprocating plate means mounted for reciprocation transversely of said working path into and out of engagement with die carrier units positioned at said single point.

5. The device of claim 1 wherein said flexible connecting means comprises links pivotally connected to said die carrier units.

6. The device of claim 1 wherein said drive means includes a rotatable sprocket member having a plurality of peripheral recesses therein for sequentially receiving said die carrier units during rotation of said sprocket member.

7. The device of claim I wherein said closed loop path is noncircular.

1 l i t 

1. A press including a frame, ram means reciprocatingly carried by said frame for reciprocation along a working path between first and second positions, a plurality of die carrier units, flexible connecting means for flexibly interconnecting said die carrier units into a closed die carrier loop, supporting guideway means for supporting and guiding said die carrier loop, said supporting and guideway means being in the form of a closed loop guide path which intersects said working path at a single point, indexing drive means for indexing said die carrier units around said guide path to sequentially position each of said die carrier units at said single point, and actuable locking means for sequentially engaging and locking said die carrier units at said single point for cooperation with said ram means.
 2. The device of claim 1 wherein said indexing drive means includes a rotatable member engaging said die carrier units in seriatim order.
 3. The device of claim 2 wherein said rotatable member is in continuous engagement with at least one of said die carrier units.
 4. The device of claim 1 wherein said locking means comprises reciprocating plate means mounted for reciprocation transversely of said working path into and out of engagement with die carrier units positioned at said single point.
 5. The device of claim 1 wherein said flexible connecting means comprises links pivotally connected to said die carrier units.
 6. The device of claim 1 wherein said drive means includes a rotatable sprocket member having a plurality of peripheral recesses therein for sequentially receiving said die carrier units during rotation of said sprocket member.
 7. The device of claim 1 wherein said closed loop path is noncircular. 